"They had given him vacation."
Translation:Le habían dado vacaciones.
Hi Iris, I think it is because the word holiday in English is always translated as vacaciones in Spanish.
That makes as much sense as I can expect, Kept. Thanks for taking the time to respond.
lo is the (masc) pronoun for direct object; le is the pronoun for indirect object. In this sentence, the direct object for the verb give (or, dar) is vacation; "him" is the indirect object, hence le. Hope that helps.
I find it helpful to think "They had given vacation to him" so that I remember that it's an indirect object.